Hydraulic ram



A. S. ANDERSON.

HYDRAULIC RAM. APPLICATION FILED JULY w, 1918.

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Patented July 12, 1921.

\ UNITED STATES PATENT OFFICE.

ALBERT S. ANDERSON, OF ST. PAUL, MINNESOTA,.ASSIGNOR T0 GRANT WALDREF, OF

. ST. PAUL, MINNESOTA. I

HYDRAULIC RAM.

of Minnesota, have. invented a new and useful Improvement in Hydraulic Rams, of which the following is a specification.

The primary object of this invention is to provide a simple and inexpensive structure which is adaptedto exert a powerful thrust movement for use in machine shops and ether places requiring a machine tool of this character. More particularlythis invention relates to that character of rams in which the fluid medium employed for exerting pressure is compressed by a gear pump and wherein the fluid medium is allowed to circulate freely through the cylinder and piston at the end of the work stroke and at the end of the return stroke. Further objects of my invention are simplicity of construction and greater effectiveness in use.

lVith these and other objects in view my invention comprises the features of construction and combination of parts hereinafter more particularly described and claimed.

In the accompanying drawing forming part of this specification, Figure 1 is a front elevation of my invention, part of the'struc ture being broken away and in section and Fig. 2 is a section of a detail taken on the line X--X of Fig.1 showing the arrangement of the pump and valve parts.

In the drawing let A indicate a suitable frame which may be of any construction desired, said frame being provided with a bed 2 and an overhead structure 3. Bolted of otherwise secured to the overhead structure is a depending cylinder 4, in which is a piston 5 forming part of the ram and having a shaft 6 slidingly passing through the gland 7 in the lower end of the cylinder, so as to exert a forceful movement in a downward direction against any work placed upon the bed 2. Arranged on the side of the cylinder is a combined pump and valve casing B, that illustrated being formed with a pair of intersecting gear pump cylinders 8 and 9 containing the pair of rotary pump gears 10 and 11, which intermesh so that when revolved they will circulate fluid medium, such as oil, through a circulating duct continuously. One of the pump gears 10 has a shaft 13 projecting from the casing B and journale d in the frame A, the outer end 'of said Specification of Letters Patent. Patented July 12, 192 1.

Application filed July 15,

1918. Serial No. 245,002.

shaft carrying a drive pulley 14 by which the pump gears are driven. Arranged above the gear pump are a pair of rotary valves 15 and 16, which are journaled in valve cylindric'al openings 17 and 18 in the casing B. The upper valve opening 18 isconnected by the pipe 19 wlth the upper end of the cylinder above the piston, while the lower valve opening 17 is connected by the duct 20 with the lower end of the cylinder below the piston. Both valves 15 and 16 are threeway valves as illustrated, the opposite ends of the duct 12 being connected by branches. 21 and 22 to the opposite sides of the valve opening 17, the ports thus produced being also connected by two branches 23 and 24: with two opposite sides of the valve opening 18. The two va ves 15 and 16 have valve stems 25 and 26 extending from the casing B, said stems being provided with a pair of intermeshing gears 27 and 28, so that when either one is turned, both valves are operated in synchronism. The stem 26 has a handle 29, by which it can be operated to move the valves. The valves 15 and 16 are so arranged that when the port opening entering the valve opening 17 which is connected with the branches 22 and 241 is closed, the port opening in the valve chamber 18 connected with the branch 24 is open. In

this position as illustrated in Fig. 2, the

ton 5 in the cylinder, thus forcing the piston down. and thrusting the ram rod 6 against any work placed below the rod on the "bed 2. This forceful movement is increasedf to a high degree by the continued revolution of the pump gears. The piston 5 is provided with a relief valve 30, which normally closes an escape passage 31 in the piston for the fluid when the piston is being forced downwardly. The valve 30 has a depending valve stem 32 which is adapted to strike against the lower end of the cylinder and open the passage 31 in the event the bed 2 is lowered and no work placed below the ram rod 6, when the piston reaches the lower end of its stroke. 1 When the passage 31 is opened by the valve, the fluid is allowed to circulate freely through the piston and through the ducts above described while the. pump gears continue to revolve freely. To reverse and lift the piston into superior position-the valves 15 and 16 are. reversed, in position so that the valve 16 will close the branch 24- and open the branch 23 allowing the fluid to circulate from above,

the pistonthrou'gh the duct '19. The valve 15 also closes the duct entering the branches 2,1 and 23 and opens the duct entering the branches ,7 22 and 24, thus causing the'fluid to be forced downwardly from above the piston'into the lower end of the cylinder lie-- low the piston. This action raises the piston .into superior position. In" the meantime, the valve is closed by a coil spring 34: placed around the stem 32 and pressing against the lower side of-the piston antl a I pin 33 on the lower end of said stem.

In the eventthe piston is forced upwardly over the opening entering the upper end of duct 19 it will strike against a stop bolt '4 35 in the upper end of the cylinder and thus be'limited in movement. The force of the fluid below the piston will then open the valve 30 against the tension of spring 34: thus allowing the fluid to circulate freely while the pump continues to operate.

have described the principles of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the construction-shown isonly illustrative and that the invention can be carried out by other means and applied to uses other than those above set forth within the scope-0 f the following claim.

Having described my invention what Iv claim as new and desire to protect by Letters Patent is:

A hydraulic'ram, comprising, in combination, a frame having a bed, a cylinder supported by'said frame over said bed, a piston in said cylinder having a shaft projecting over said bed, a pair of valves, a gear pump having ingress and egress ducts connected in multiple With said valves, a duct leading from the upper end of said cylinder to one of said valves, another duct leadingfrom the lower end of said cylinder to the other of said valves, said valves in one position being adapted to direct the flow of liquid from said pump in one direction through said cylinder and in another position to reverse the flow of liquid through said cylinder, means for simultaneously operating said valves and means for driving said gear pump.

Intestimony whereof, I have signed my name to this specification.

ALBERT s. ANDERSON. 

